Field of the Invention
The invention relates to an aerosol filter having a number of coaxially disposed, approximately cylindrical filter areas.
During filtration, a medium to be filtered flows through a filter. In this case, depending on the type of medium to be filtered, a distinction is made between various filter types. To separate oil, aerosols or coalescers from the air or from liquids, aerosol filters (high-efficiency particulate air filters), as disclosed, for example, by the publication Dubbel "Taschenbuch fur Maschinenbau" (Pocketbook for Mechanical Engineering), 16th edition, Springer 1987, page M48, are normally used.
In such an aerosol filter having a number of coaxially disposed, approximately cylindrical filter areas, the medium to be filtered flows through the latter from inside to outside. In this case, the enlargement of the filter areas due to the increase in the cylinder radii brings about a decrease in the flow velocity of the medium through the filter area with increasing cylinder radius. This reduction in the flow velocity leads to intensified coalescing of oil droplets or aerosol particles. Finally, the oil droplets or aerosol particles, which thus become larger, are deflected from the direction of flow of the medium by the force of gravity on account of their increasing weight and are thus separated.
The filter areas normally consist of ceramic elements, glass fibers or synthetic nonwovens. However, these materials tend to absorb deposits of the medium to be filtered and therefore tend to become clogged. Such an aerosol filter therefore has to be exchanged even after a short time and replaced by new aerosol filters. However, in particular during the filtration of toxic or radioactive substances, any waste containing these substances is to be avoided.